commit c00cc43e53164424d931610609615f8f51e565b2
author Ben Clayton <bclayton@google.com> Wed Jan 05 20:42:50 2022 +0000
committer Tint LUCI CQ <tint-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jan 05 20:42:50 2022 +0000
tree 01188718305d6dde688f5289ed51c20f3f848222
parent 1c4f8de30b516802cb125188b71dd043dda678cf

reader/spirv: Optimize FindUnusedDerivedName()

Store the last search id suffix so that we don't research the same suffixes over and over again.

Bug: oss-fuzz:38098
Bug: oss-fuzz:38606
Bug: oss-fuzz:39300
Bug: oss-fuzz:40339
Change-Id: I295147d91bb9f805170c49114267033bbb781e4d
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/75427
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>

src/reader/spirv/namer.cc

diff --git a/src/reader/spirv/namer.cc b/src/reader/spirv/namer.cc
index 4d819b4..c2b2e98 100644
--- a/src/reader/spirv/namer.cc
+++ b/src/reader/spirv/namer.cc
@@ -104,20 +104,24 @@
   return result;
 }
 
-std::string Namer::FindUnusedDerivedName(const std::string& base_name) const {
+std::string Namer::FindUnusedDerivedName(const std::string& base_name) {
   // Ensure uniqueness among names.
   std::string derived_name;
-  int i = 0;
-  do {
+  uint32_t& i = next_unusued_derived_name_id_[base_name];
+  while (i != 0xffffffff) {
     std::stringstream new_name_stream;
     new_name_stream << base_name;
     if (i > 0) {
       new_name_stream << "_" << i;
     }
-    i++;
     derived_name = new_name_stream.str();
-  } while (IsRegistered(derived_name));
-  return derived_name;
+    if (!IsRegistered(derived_name)) {
+      return derived_name;
+    }
+    i++;
+  }
+  TINT_ASSERT(Reader, false /* FindUnusedDerivedName() overflowed u32 */);
+  return "<u32 overflow>";
 }
 
 std::string Namer::MakeDerivedName(const std::string& base_name) {